Non-destructive Real Time Monitoring of the Laser Welding Process

Laser welding is a high power density technology of materials joining that has many advantages in comparison with conventional fusion welding methods, for example, high accuracy, flexibility, repeatability and especially very narrow heat-affected zone which results in minimal workpiece distortions. Since it is still quite expensive technology, minimal spoilage is required. Effective system of quality control and processing parameters optimization must be established to reduce total costs, which is particularly required in industrial production. In this article some results of pulsed Nd:YAG laser welding process monitoring based on the measurement of plasma electron temperature are presented. The ability of designed sensor to detect weld penetration depth has been demonstrated. Plasma spectral lines intensities measurement can discover gap instabilities as well as local sheet thickness reduction.     

激光表面强化和再制造技术的研究与应用进展

激光表面技术是一种先进的表面工程技术,已越来越多地应用到工业生产中,许多关键基础部件由于采用激光强化与再制造技术实现了高性能低成本制造,并改造了传统制造方法。从材料、工艺与装备对当今国内外对激光表面强化与再制造技术的研究现状做了系统阐述,分析了存在的几个难点并提出解决途径。详细介绍了国内外激光表面技术工业应用情况,深入分析了该技术领域的发展趋势与现今所面临的挑战。     

材料表面激光抛光技术研究进展∗

抛光技术是现代制造产业的关键技术之一,现代制造工艺的发展对材料抛光精度的要求已经达到了微纳级。 与传统抛光技术相比,激光抛光技术更容易满足工业要求,并且适用于金属、陶瓷、玻璃等多种材料,在抛光加工领域受到了国内外学者的广泛关注。 综述了近年来不同材料激光抛光技术的研究进展;针对激光抛光过程中产生的热应力,分析了工艺参数以及温度变化对激光抛光效果的影响,探讨了新型的激光抛光技术,梳理了将激光抛光与其他抛光技术进行有效复合的方法与观点。 按照不同的材料,归纳了激光抛光技术的作用机理,并阐述了激光抛光技术的优缺点,最后对激光抛光技术的未来发展进行展望。 对于目前激光抛光研究中尚未解决的问题以及未来不同材料的激光抛光技术的研究方向具有指导意义。     

等离子喷涂技术的现状与展望

最近发达的工业国家在等离子喷涂技术的开发研究和生产应用方面取得了长足的进步。相比之下，我国则进展不大。文中综合分析了国内外等离子喷涂技术的现状，并着重阐述了今后的发展趋势。本文旨在抛砖引玉，以期这一技术在我国的工业生产中发挥更大的作用。     

关于大功率CO2激光器在船舶制造中应用的探讨

文章介绍了在欧洲一些工业发达国家激光焊接技术在船舶制造中应用的发展历程和现状,指出了大功率CO2激光器在船舶制造应用中需要解决的问题:光束传输与变换、激光焊接过程中激光束与焊缝中心的对位以及激光焊接技术在船舶制造中应用的经济性,进而指出激光焊接技术在船舶制造的应用研究中不仅要从激光焊接技术的工艺可行性入手,还要从光束传输、设备制造、焊缝跟踪以及船体结构等方面入手进行多方面的研究.     

激光冲击成形控制系统设计与应用

激光冲击成形技术是一项尚处于实验室研究阶段的板料成形新技术,本文根据激光器的工作特性和激光冲击成形实验的要求设计了相应的控制系统及其软件,该控制系统以一台工控机作为主机,两台单片机为从机,再加若干辅助设备,构成了一个基于RS-485总线的控制系统,系统的控制对象为激光器高功率脉冲电源和一个五自由度机械平台.实际使用效果表明该控制系统完全满足目前激光冲击成形研究的需要.     

Laser powder technology for cladding and welding

Laser powder technology offers several advantages compared to conventional cladding and welding techniques and is attracting increasing industrial interest. The laser materials processing group of the German Aerospace Center at Stuttgart, Germany, is currently developing these new methods for application in industrial process engineering. Key areas of the work include the design and implementation of a modular working head that can be universally used for laser welding and surface treatment, the development of powder nozzles for cladding and welding, and the construction of new systems for special applications (e.g., for inner cladding). Some of these developments are described, as well as some important examples that highlight the potential of welding and surface treatment using laser powder techniques.     

清洁生产与水压传动技术

环境、生态、资源已成为全社会人类关注的焦点问题。随着世界各国环境与清洁生产法规的制定,清洁生产已成为各国解决发展与环境、资源问题的根本途径,是2l世纪工业化生产的基本模式,也是世界各国发展新型经济,走新型工业化发展道路,实施可持续发展战略的必然选择。水压传动技术是基于绿色设计和清洁生产技术而发展起来的一门新技术,是清洁生产发展过程中的一个重要里程碑。本文阐述了清洁生产产生的背景以及清洁生产的含义、特点、内容、常用的清洁生产工具及主要的实施途径。简述了水压传动技术发展的历史进程及其清洁生产特征。探讨了水压传动技术在清洁生产中的工业应用以及清洁生产与水压传动技术的相互关系。     

激光焊接过程视觉传感技术的发展现状

比较了目前激光焊接过程监测中常用的CCD和CMOS两种类型视觉传感器的性能,介绍了激光焊接过程视觉传感技术的难题及其解决方案以及常用的成像信号提取光路,综述了激光焊接过程同轴和旁轴视觉传感技术的各自特点以及国内外在这方面的研究现状.分析认为,日本在主动视觉传感技术研究方面比较先进,而德国在被动式同轴视觉传感检测的研究上处于领先地位,并且已有成型的产品推出.国内在这方面的研究已经起步,但与国外相比在系统研发上还有较大差距.目前激光焊接过程视觉传感检测技术主要用于激光焊接机理等研究工作,将其应用于实际生产是激光焊接过程视觉监测技术的研发方向.     

金属表面腐蚀层及涂层的激光干式清洗研究进展

激光干式清洗方法,因操作简单、清洗过程易于控制等优点,目前应用最为广泛。重点介绍了激光干式清洗在各种金属材质表面不同腐蚀层和涂层清除中的应用,包括有多种钢材表面的锈层,钢材表面的ZrO2、Cr2O3、Al2O3变性层,热轧钢表面高温氧化层,Ti合金表面富氧α相层,合金钢在H2S环境中腐蚀而形成的硫化层,钢、铝合金、钛合金表面漆层,热压成型钢板表面Al-Si涂层以及航空压缩机Ti合金叶片TiAlN涂层等。分类对比了不同清洗对象所需选用的合适激光清洗工艺参数,如波长、脉宽、频率、功率、扫描速率等。金属材料激光干式清洗多选用波长为1064 nm的纳秒激光器,清洗后表面粗糙度可达1μm,且随着能量输入的升高而增大。锈层的去除主要依靠高温烧蚀作用,变性层是由于产生的热弹性应力而剥离,而漆层和涂层则是由于烧蚀气化、热振动、热冲击等机制实现清洗。最后,对激光清洗技术在国内不同工业领域中的应用前景进行了展望。     

激光超声技术及其应用

综述了激光超声技术的基本特点,介绍了激光超声产生机理及检测方法。概述了激光超声技术在工业无损检测技术中的应用。得出激光超声技术作为一种新兴技术,具有非接触、远距离、高时空分辨力等特点,将在工业无损检测中具有十分广泛的应用价值。     

激光制造在国内外船舶制造中的应用与前景

激光制造是对一个国家国民经济影响最大的激光技术应用领域,包括船舶在内的运输机械轻型化和短流程制造是工业发展的新方向,激光是实现这一目标的首选手段.简单介绍了激光制造在国内外的应用现状,通过对影响激光制造过程的关键光束特性的分析,探讨了激光技术在船舶制造中的优越性、经济性以及可行性,最后介绍了现代激光制造技术的应用前景.     

板带热连轧自动化系统的现状与展望

我国钢铁工业取得了长足的进步, 从工艺技术、产品结构、设备应用以及技术管理方面正逐步向国际先进水平靠拢。生产高技术、高附加值的热轧板带材是我国钢铁工业现阶段的首要任务。本文主要介绍了国内外热连轧生产的发展历程, 并对热连轧的先进控制技术进行了综述, 同时对我国热轧带钢生产企业的未来发展进行了展望。     

Advances in macro-scale laser processing

Laser material processing is a technology with an increasing number of industrial applications, especially for aviation and automotive. The present keynote paper focusses on the advances in macro-scale laser processing, meaning that the laser generated structures are large enough to be visible with the naked eye. Next to that, also the reasons for the advances, especially the improvements regarding the power and the beam quality of the laser sources, the higher capabilities of the systems technologies and an increasing process understanding are shown. Nevertheless, challenges like a holistic understanding of the physical phenomena and the evolution of defects in some processing methods remain to be solved in future.     

从铝电解生产新技术看我国与国际水平之差距

本文对我国电解铝厂与国外电解铝厂在主要技术方面的差距进行了分析，介绍了国外最先进的铝电解技术。阐述了我国电解铝厂在技术方面所存在的问题。作者认为，采用国外最先进的铝电解技术研究成果，并结合我国国情开发自主知识产权的技术，可使我国铝电解的技术尽快地达到世界先进水平。     

激光淬火技术在模具表面处理中的应用与展望

简述了通过模具生产零件的优点及其在工业生产中的地位,而且对模具使用寿命的影响因素进行了分析,并对模具失效的主要形式做了简要说明。总结了以往人们对金属进行表面改性几种主要的工艺方法,将激光淬火技术与传统的热处理工艺进行了对比,并指出了激光淬火的优点。总体概括介绍了激光淬火技术的发展历史、激光淬火硬化机理,指出了影响激光淬火工艺的参数和确定三种主要影响因素大小的试验方法,并分析了激光淬火处理后工件不同深度的组织形成过程和相应的各项性能,尤其是对第一层的相变硬化层形成过程中的原子扩散机理作了详细说明。针对提高材料表面吸收激光率而预处理的有效方法及优点进行了论述。简述了激光淬火过程中常用激光器有CO2激光和YAG激光及相应的用途。列举了热作模具、冷作模具、塑料模具各种不同钢经不同的激光淬火参数淬火后,其硬化层的组织和相应的显微硬度,指出了这三种模具钢利用激光淬火的主要目的。最后对激光淬火技术的优缺点作了总结,并对模具表面激光改性的未来进行了展望。     

Effect of the composition on the hardenability and properties of complexly alloyed steel for large-size parts

Large-sin parts are usually produced from steels with high hardenability. Intermediate-carbon improved chromium-nickel steels containing 1–3% Ni are used successfully for this purpose in Ukraine and in foreign countries. However, nickel is an expensive and scarce alloying element. The present work is devoted to steels with different compositions with the aim of choosing the most suitable one for large-size parts. The effect of alloying elements on the hardenability and mechanical properties of steels is investigated. A mathematical model is obtained.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 13–17, May, 1995.     

CCS-B船用钢板的不同激光焊接工艺分析

激光焊、激光填丝焊以及激光复合焊技术日趋成熟,并被一些著名船厂应用到生产上.我国造船业的激光应用研究正处于起步阶段.CCS-B是我国相当普遍的一种船用低碳钢,通常采用传统工艺进行焊接.采用以上的激光焊接工艺对CCS-B进行堆焊和对接焊,对它们宏观焊缝的差异进行分析,对相应焊缝金属的微观组织进行观察和分析.焊接金属的合金成分会影响其微观组织的形成,采用ICP-AES法对不同激光焊接工艺下的焊缝金属成分进行了检测分析.同时对接头截面的硬度进行了测试.     

Characterization of the drilling alumina ceramic using Nd:YAG pulsed laser

Laser micromachining can replace mechanical removal methods in many industrial applications, particularly in the processing of difficult-to-machine materials such as hardened metals, ceramics, and composites. It is being applied across many industries like semiconductor, electronics, medical, automotive, aerospace, instrumentation and communications. Laser machining is a thermal process. The effectiveness of this process depends on thermal and optical properties of the material. Therefore, laser machining is suitable for materials that exhibit a high degree of brittleness, or hardness, and have favourable thermal properties, such as low thermal diffusivity and conductivity. Ceramics which have the mentioned properties are used extensively in the microelectronics industry for scribing and hole drilling.Rapid improvement of laser technology in recent years gave us facility to control laser parameters such as wavelength, pulse duration, energy and frequency of laser. In this study, Nd:YAG pulsed laser (with minimum pulse duration of 0.5 ms) is used in order to determine the effects of the peak power and the pulse duration on the holes of the alumina ceramic plates. The thicknesses of the alumina ceramic plates drilled by laser are 10 mm. Average hole diameters are measured between 500 μm and 1000 μm at different drilling parameters. The morphologies of the drilled materials are analyzed using optical microscope. Effects of the laser pulse duration and the peak power on the average taper angles of the holes are investigated.     

Laser beam cladding: A flexible tool for local surface treatment and repair

The versatility of the laser beam cladding process as a means of localized surface treatment is highlighted in this article with an emphasis on applications in the field of repair and regeneration. A newly developed cladding technology using low power Nd:YAG lasers is also introduced. Small dimensions and minimal heat input allow high precision cladding. Short interaction times and good control of the process enable the generation of graded composite coatings. Application examples in the field of regeneration of components are given. An industrial case study presents the CO₂ laser repair of large engine components.